﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;

class Program
{
    static List<string> ReadLines()
    {
        List<string> evenLines = new List<string>();
        StreamReader file = new StreamReader("test.txt");
        int lineNumber = 0;
        using (file)
        {
            string line = file.ReadLine();
            while (line != null)
            {

                if (lineNumber % 2 == 0)
                {
                    evenLines.Add(line);
                }
                line = file.ReadLine();
                lineNumber++;
            }
        }
        return evenLines;
    }
    static void WriteLines(List<string> evenLines)
    {
        StreamWriter newFile = new StreamWriter("test.txt");
        foreach (string line in evenLines)
        {
            newFile.WriteLine(line);
        }
    }
    static void Main(string[] args)
    {
        WriteLines(ReadLines());
    }
}
     
     
      
      
    